Air conditioning system



March 12, 1940. a ANDERSON 2,193,153

AIR CONDITIONING SYSTEM Filed Dec. 2, 1937 ICE NA 752 sol/RC5 EL ECTE/C SOUECE INVENTOR. \S'AMUEL M ANDERSON BY %J M ATTORNEY.

Patented Mar. 12, 1940 UNITED STATES PATENT OFFICE 2,193,153 I AIR CONDITIONING SYSTEM Mass.

Application December 2, 1937, Serial No. 177,830

8 Claims.

This invention relates to air conditioning systems and relates more particularly to spray type air conditioning systems for passenger vehicles. Spray type air cooling systems are preferred for passenger vehicles; such for example, as railway passenger cars for not only is temperature" and humidity under better control but the air is cleaner, free from odors and is more refreshing. Another advantage of spray type systems is that they may be operated in evaporative cooling fora ing and evaporative cooling cycles during the hot summer months. It has been the practice however, to discontinue using the sprays in the winter months because of the difliculties due to condensation on window panes and it has also been the custom to discontinue the use of the sprays during the spring and fall months when little or no cooling is required.

A feature of this invention resides in the provision of means whereby the sprays may be efs fectively used with or withoutheat during those border line days between the heating and cooling seasons. This is advantageous since the use of the sprays for cleaning and purifying the air is extended over a much larger period of time.

Another feature of this invention resides in the' provision of automatic controls for converting a. spray system from evaporative cooling to refrigerative cooling; for converting the system from cooling to heating, and for efllciently and ef- 35 fectively maintaining the desired indoor conditions at all times. a

An object of the invention is to provide eflicient,

effective controls for air conditioning systems.

Another object of the invention is to provide 40 combined summer, winter and intermediate season controls for an air conditioning system.

Other objects of the invention will be apparent from the following description taken together with the drawing.

' The invention will now be described with reference to the drawing which illustrates diagrammatically, one embodiment of an air conditioning system according to this invention. The spray type .air conditioner indicated generally by 5 is mounted in one end and in the roof zone of a railway passenger car. The fan 6 draws fresh air through the vestibule grille I, and recirculated air through the recirculated air inlet v grilles l and 9 and forces it through the unit 5 and then into the passenger space through any suitable air distributing duct.

. The unit 5 contains the steam coils ll) supplied from the source ll through the .valve l2 controlled by the solenoid l3 as will be described later. The unit 5 also contains the spray nozzles H which are supplied by the pump l5 with recirculated water for evaporative cooling from the sump 16, or withice water for refrigerative cool-' ing from the source I! as will be explained later. The pipe l8 carries the drain water from the sump IQ of the unit 5 to the water collecting.

sump l6 which is preferably mounted on the under side oithe car. The ice water source H which may contain ice or may contain evaporator coils for the supply of the ice water,-is preferably mounted along-side the sump ,IG and receives water during the refrigerative cooling cycle from the sump l6 through the pipe IS. The pipes l9 connect the outlet of the ice water source I! with the three-way valve for supplying ice water to the pump [5 during the evaporative cooling cycle. The pipes 2| connect the valve 20 with the pipe l8 and form a by-pass around the ice water source I! for supplying water from the sump I6 to the pump I5 during the evaporative cooling cycle.

The thermostat 22 in the path of the fresh outdoor air entering the conditioner is connected in an electric circuit including the motor 23 for adjusting the shutters 24 in the recirculated air inlet 8, the electric source 25, the contacts of the relay 26 and the solenoid 21. This thermostat '22 is responsive to changes in the wet bulb temperature of the outdoor air and acts when the wet bulb'temperature is below 62 F. to close the above described electric circuit causing the motor 23 to close the. recirculated air shutters 24 and causing the solenoid 21 to actuate the valve 20 to admit water through the by-pass and to close off the supply of water through the pipes I! which supply ice water. The contacts of the relay 25 are closed at this time for it is provided, as will be explained later, for opening the above described circuit under control of the thermostat 28 when the system is converted from cooling to heating. At this time, the shutters 29 in the recirculated air inlet 9 are closed under control of the thermostat 30 which maintains the shutters 29 closed for outdoor wet bulb temperature below 50 as will be explained later.

Due to the operation of the by-pass around the ice water source I1, the spray water is continuously recirculated for evaporative cooling. Due to the closing oil of the recirculated air inlet to operate the valve 20 to close off the by-pass around the ice water source and to permit the pump |5 to draw water from the ice water source l1. The motor 23 opens the shutters 24 to permit recirculated air to enter the conditioner. I

During both the evaporative and the refrigerative cooling cycles above described, the indoor thermometer 3| maintains the desired temperature in the passenger space by closing and opening the circuit including the thermostat 3|, the electric source 32, the contacts of the relay 33 and the pump motor 34 causing the pump to supply water to. the spray nozzles I4 when the temperature is above the desired level and the supply of vwater to be discontinued when the temperature is at or'below the desired level. The contacts of the relay 33 remain closed at this time under control of the thermostat 28 which shuts down the pump |5 during the heating season as will be described later.

The system operates in evaporative cooling during the spring and fall months when but little cooling and occasional heating is required. If when operating under evaporative cooling the outdoorwet bulb drops to 50 F., the thermostat 30 closes a circuit including the damper control motor 35, the electric source 25, the contact of the relay 3B and the thermostat 31. The thermostat 31 then functions when the indoor temperature is too low, to open the recirculated air dampers 29 to admit warm'recirculated air into the conditioner for the purpose of raising the temperature of the delivered air.

If the outdoor wet bulb drops to 47, the thermostat 39 closes a circuit including the electric source 25, the solenoid 13, the winding of the relay 36 and the indoor thermostat 38. When the outdoor wet bulb temperature has dropped as low as 47 F., the indoor thermostat operates the solenoid l3 to open and close the steam valve |2 thus controlling the supply of heat from the steam source II to the air heating coils: l0. At this time, the relay 36 is energizedand its contacts separate to disconnect the thermostat 31 and the shutter motor 35 from its energizing circuit. The motor 35 then permits the shutters 29 to close.

During the periods the thermostat 31 adjusts the recirculated air dampers and the thermostat 38 adjusts the steam valve, the thermostat 3| functions to control the sprays. The thermostat 3| may beset to function at a slightlyhigher temperature than the thermostats 31 and 38.

Then when the indoor temperature drops below' its setting it turns olf'the sprays. If this is not suflicient-the indoor temperature will drop tothe setting of the thermostats 31 and 38 which will then function to add heat to the air.

When the outdoor wet bulb temperature drops to 35, the thermostat 28 converts the system from cooling to heating. It does this by closing the electric circuit including the winding of the relay 26, the winding of the relay 33 and the electric source 25. This energizes these two relays and the contacts of the relay 26 separate to open the circuit of the shutter motor 23causing it to permit the recirculated air shutters to open. The

contacts of the relay 33 separate to open the circuit including the pump motor 34 causing the sprays to be discontinued.

During the heating season, the thermostat 38 functions as previously described; to control the supply of steam to the coil In,

. Instead of, as formerly, the sprays being shut down on the first day any heat was required, according to this invention they function on those border line days when heat may or may not be required. If heat is required, there is. no inefliciency through the system being operated first to cool and then to heat as this is controlled according to indoor conditions. Due also to the entire system for both heating and cooling being under thermostatic control, those irregularities in heating and cooling resulting from the discretion and inattention of the car attendant, are removed.

In the foregoing, it has been described that when the temperature in the passenger space reached a predetermined point the thermostat 3| shuts down the sprays and then during the time the outdoor temperature is below a predetermined point, if the air within the passenger space is still too cold, the thermostats 31 or 38 would function to add-meat to the air. Under favorable conditions it may be desirable to shunt the thermostat 3| out of the circuit of the motor 34 for outdoor wet bulb temperatures below 50 so that the sprays will operate continuously with the temperature within the passenger space controlled as described by the thermostats 31 and 38. This would be accomplished by utilizing an additional relay or additional relays which would be energized by the thermostat 38' or by the thermostats 30 and 39, to shunt the thermostat 3| out of its energizing circuit when the thermostats 30 and 39 acted to energize the thermostats 38 and 31 respectively.

The thermostats exposed to the outside air entering the car have been described as responsive to certain wet bulb temperatures. This description has however, been by way of example and the thermostats could operate at other temperatures than those described. The thermostats 28, 38 and 39 could be dry bulb thermostats. The thermostat 22 could bea combination dry bulb thermostat and hygrostat responsive to changes in the wet bulb temperature.

While one embodiment of the invention has been described for thepurpose of illustration, it should be understood that the invention not be limited to the precise arrangement described,

since many departures may be suggested by those skilled in the art, without departing from the spirit of the invention.

What is claimed is:

1. An air conditioning system for a passenger vehicle comprising a spray cooler, means for supplying outside air into said cooler, a source of refrigerated water, supply means connecting with said source for supplying water from said source to said cooler, a sump for receiving water from said cooler, means forming a by-pass around said source and connecting with said supply means for supplying water from said sump to said cooler, thermostatic means responsive to outside wet bulb temperature changes for operating said by-pass when the wet bulb temperature of the outside air is sufliciently low for evaporative cooling to be effective, means for supplying air recirculated from the passenger space into said cooler, means responsive to temperatures in said passenger space for adjusting said last mentioned means, and means responsive to outside temperature changes for rendering said last mentioned means effective for outside temperatures below a predetermined point and for rendering same ineffective for outside temperatures above said point.

2. An air conditioning system for a passenger vehicle comprising a spray cooler, means for supplying outside air into said cooler, a. source of refrigerated water, supply means connecting with said source for supplying water from said source to said cooler, a sump for receiving water from said cooler, means forming a icy-pass around said source and connecting with said supply means for supplying water from said sump to said cooler, thermostatic means responsive to outside wet bulb temperatures for operating said by-pass when the wet bulb temperature of the outside air is below a predetermined point, means for supplying air recirculated from the passenger space into said cooler, and means responsive to outside temperatures and to temperatures in said. passenger space for adjusting said last mentioned means to decrease the volume of recirculated air when the outside temperature falls to a prede= termined point below said first mentioned point and the temperature in said passenger space falls below a predetermined point.

3. An air conditioning system comprising an air washer, means for supplying water to said washer, means for supplying recirculated air from the space served into said washer, means for supplying outdoor air into said washer, an outdoor -air thermostat, and means controlled by said thermostat for adjusting said first and second means for decreasing the volume of wa ter supplied to said washer and for increasing the volume of recirculated air into said washer when the outdoor temperature falls below a predetermined level.

4. An air conditioning system comprising an air conditioner, means for supplying recirculated air from the space served into said conditioner, means for supplying outdoor air into said conditioner, an indoor thermostat for adjusting said recirculated air supply means, an outdoor thermostat, and means controlled by said outdoor air thermostat for rendering said indoor thermostat effective when the outdoor air falls below a predetermined level.

5. An air conditioning system comprising-an air conditioner, means for supplying recirculated air from the space served into said conditioner,

means for supplying outdoor air into said condiair conditioner, means for supplying recirculated air from the space served into said conditioner, means for supplying outdoor air into said conditioner, an indoor thermostat for adjusting said recirculated air supply means, an outdoor thermostat, means controlled by said outdoor air thermostat for rendering said indoor thermostat effective when the outdoor air falls below a pre- 4 determined level, an air heater associated with said conditioner, a second indoor thermostat for controlling the effectiveness of said heater, a sec-- and outdoor thermostat, and means controlled by said second outdoor thermostat for rendering said first mentioned indoor thermostat inefiective and for rendering said second indoor thermostat effective when the outdoor temperature falls to a predetermined level below said first mentioned level.

7. An air conditioning system comprising an air washer, means for supplying water to said T? washer, means for supplying recirculated air from the space served into said washer, means for supplying outdoor airinto said washer, an indoor thermostat for adjusting said first mentioned means for decreasing the supply of water to said washer when the indoor temperature falls to a predetermined level, and a second indoor thermostat for controlling the volume of recirculated air supplied by said second mentioned means for increasing the volume of recirculated air when the indoor temperature falls to a level below said first mentioned level.

8. An air conditioning system for a passenger vehicle comprising a spray cooler, means for supplying outside air into'said cooler, a source of refrigerated water, supply means for supplying water from said source to said cooler, a sump for receiving water from said cooler, means forming a by-pass around said source and connecting with said supply meansfor supplying water from said sump to said cooler, thermostatic means responsive to wet bulb temperature changes for operating said by-pass when the wet bulb temperature of the outsideair is low enough for evaporative cooling to be effective, means for supplying air recirculated from the passenger space into said; cooler, means responsive to temperatures in the passenger space for adjusting said last mentioned means, means responsive to outside temperature changes for rendering said last mentioned means effective for outside temperatures below, a predetermined point and for rendering same inefiective. for outside temperatures above said point, another means exposed to temperatures in said passenger space for controlling the volume of water supplied by said supply means to said cooler, and means responsive to outside temperature changes for rendering said last mentioned means ineffective for outside temperatures below a predetermined point and for rendering same effective for outside temperatures above said last mentioned P int.

' SAMUEL M. ANDERSON. 

